… here are some paragraphs taken from a blog post by a jiu jitsu practitioner who talks about the various pressures that can be trained for. I think he communicates quite well, the physicality of Pressure and Pressure as a valid player in a confrontation.

“Physically, pressure manifests through superior technique, superior pace/conditioning and strength, usually in the form of pressure being exerted on a person. At the same time, mental pressure has a lot to do with it, as well. Mentally, pressure has a lot to do with perception, coming from within, although even here it can have a lot to do with one’s opponent….

… But beyond this technical pressure, there are guys who create a sense of urgency in their opponents. I roll with some guys and they never settle in. They move from one position to another gracefully and give the sense that they’re always one step ahead (whether they are or not). This is a different kind of pressure, but it’s just as important. New guys lock in. White belts tend to close their guard and hold on for dear life. This is the pressure that you experience when you’re rolling with someone who makes you feel like every move you make is exactly the wrong one.

Related to the last are the pressures that come from pacing and conditioning. This is the kind of pressure that guys can exert by just being energizer bunnies. Always moving, always attacking. What makes this different from the last, is that this is independent of skill really. Instead of creating a sense of urgency in my opponent by staying ahead of them strategically, I’m really just going flat out, balls to the wall crazy. In a white belt, this will often lead to a lot of tapping out. As we get more technique, however, it can create opportunities as long as the technique is sound….

….Mentally, we tend to be our own worst enemies. Pressure can come from a perception of inferior physical ability or skill. “I’m not going to try to sweep him. He’s too big.” Or maybe, “I’ll never catch him. He’s a black/brown/purple/blue/whatever belt.” I’m not sure what I can really say about this. I think I’m among the worst around when it comes to dealing with self-derived stress. What do I do to break out of this? Well, I try to compete when I can. I try to spar with guys who I know I don’t match up well against. These are the guys who kill me every time.

This kind of mental pressure can also be cultivated by gaining a reputation with certain techniques or positions. “Oh, man. So and so has a killer half guard game. Get caught in that and it’s over.”